Report of Business Segments (Tables)

3 Months Ended

Mar. 31, 2014

Segment Reporting [Abstract]

Schedule of Segment Reporting Information, by Segment [Table Text Block]

The following tables summarize the results of the Company's business segments during the threemonths endedMarch 31, 2014 and 2013.

Three Months Ended March 31, 2014	Electric Utility		Natural Gas Midstream Operations		Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	560.4	$	—	$	—		$	—		$	560.4
Cost of sales	293.4		—		—			—			293.4
Other operation and maintenance	117.1		—		(4.7		)	—			112.4
Depreciation and amortization	64.3		—		2.9			—			67.2
Taxes other than income	23.8		—		1.8			—			25.6
Operating income (loss)	$	61.8	$	—	$	—		$	—		$	61.8
Equity in earnings of unconsolidated affiliates	$	—	$	47.9	$	—		$	—		$	47.9
Investment in unconsolidated affiliates (at historical cost)	$	—	$	1,314.2	$	—		$	—		$	1,314.2
Total assets	$	7,826.8	$	1,367.4	$	127.9		$	(71.4	)	$	9,250.7

Three Months Ended March 31, 2013	Electric Utility		Natural Gas Midstream Operations		Other Operations			Eliminations			Total
(In millions)
Operating revenues	$	455.5	$	464.3	$	—		$	(18.4	)	$	901.4
Cost of sales	213.0		359.2		—			(19.2		)	553.0
Other operation and maintenance	105.1		45.2		(2.3		)	—			148.0
Depreciation and amortization	61.3		27.6		3.0			—			91.9
Taxes other than income	23.2		8.0		1.9			—			33.1
Operating income (loss)	$	52.9	$	24.3	$	(2.6	)	$	0.8		$	75.4
Total assets	$	7,138.4	$	2,729.9	$	381.6		$	(268.1	)	$	9,981.8